1. Field of the Invention
The present invention relates to a numerical control information generating apparatus that generates numerical control information used for numerical control machining and, in particular, to a numerical control information generating apparatus characterized by the utilization of a machining method in which the determination and cutting conditions are set.
2. Description of the Prior Art
Numerical control information generating apparatuses have been put to practical use which generate numerical control information such as NC programs according to design drawings by accepting necessary data on an interactive basis using a figure display device.
In such numerical control information generating apparatus, machining shapes can be input by depressing corresponding keys, buttons or the like on an operation panel according to the shapes of parts described in a design drawing. Various data such as dimensions can be input in response to enquiries using everyday language. In addition, the instant all data necessary to determine a shape is input, the shape is drawn on a screen, and thus, whether the input data is correct or not can be confirmed. When all data necessary to generate numerical control information is input, numerical control information is generated automatically by calculations in accordance with machining conditions which have been previously set, and a tool path is graphically displayed. When the operator makes a judgement that it is desirable to optimize the numerical control information in which various conditions at the time of machining are taken into account, the tool path and cutting conditions can be corrected on an interactive basis.
The above-described conventional numerical control information generating apparatus will be explained with reference to the block diagram of FIG. 1.
An input device 1 is a device such as an operation panel, which is provided with various operation buttons and keys. A display device 2 is a character and figure display device. An operator operates the numerical control information generating apparatus using the input device 1 and the display device 2. Displayed on the display device 2 are guidances concerning such matters as machining conditions correction, machining shape input, numerical control information generation, numerical control information correction and numerical control information output. By operating operation buttons or keys of the input device 1 that correspond to guidance displays, each of the processing sections can be invoked. If operation buttons or keys corresponding to machining conditions correction are operated, a machining conditions correction processing section 3 is invoked. This machining condition correcting section 3 enables machining conditions of a machining condition storage section 4 to be corrected prior to the generation of the numerical control information. As shown in FIG. 2, the machining conditions consist of a machining direction determination value AR and data denoting the cutting condition table. Guidance is displayed on the display device 2. If the operation buttons or keys of the input device 1 corresponding to correction items are operated by following the data of the display, the current set values and guidances are displayed on the display device 2. The input of new values set via the operation buttons or keys of the input device 1 causes the machining conditions to be corrected. The machining condition storage section 4 is composed of storage devices whose contents are not erased even if the power supply of the numerical control information generating apparatus is cut off due to accidents, etc. Therefore, the values which have been set are retained until they are reset.
When the operation buttons or keys corresponding to the machining shape input are operated, a machining shape inputting section 5 is invoked. This machining shape inputting section 5 enables the operator to input machining shapes to a machining shape storage section 6 according to design drawings. A machining shape consists of a machining shape CF and a material code M, as shown in FIG. 3. First, a material code is input via the operation buttons or keys of the input device 1 by following the guidance display of the display device 2. Next, if the operation buttons or keys of the input device 1 corresponding to shape elements such as a straight line and an arc are depressed, guidances concerning such matters as coordinate values and radiuses, are displayed on the display device 2. Necessary shape elements are input one by one by the operation such that the numerical values written on the design drawing are input through the input device 1 in accordance with the guidance display. Thus a machining shape is input. In addition, when the operation buttons or keys corresponding to numerical control information generation are operated, a numerical control information generating section 7 is invoked. This numerical control information generating section 7 reads out a machining shape and machining conditions, and numerical control information is formed in a numerical control information storage section 9. The numerical control information consists of a tool path CP, a machining direction code CM, cutting conditions, etc., as shown in FIG. 4.
The operations of the numerical control information generating section 7 will now be explained with reference to a flow chart shown in FIG. 5.
First, a lateral size H, a longitudinal size V and a machining radius R of FIG. 3 are determined on the basis of the machining shape CF (Step S1). Such data is determined by surveying all the coordinate values of shape elements, such as straight lines and arcs, forming the machining shape CF and by defining the difference between a maximum value and a minimum value of Z-coordinates to be the lateral size H, one half the difference between a maximum value and a minimum value of X-coordinates to be the longitudinal size V and one half the minimum value of the X-coordinate to be the machining radius R. Next, "H/(H+V)" is calculated. This value is compared with the machining direction determination value AR. Thus, whether the machining shape CF is longer sideways or lengthways than the shape indicated by the machining direction determination value AR can be determined (Step S2). When the value "H/(H+V)" is greater than the machining direction determination value AR, the machining shape CF is long sideways, and a numeral "1" indicating the longish direction is set in the machining direction code CM (Step S3). When, on the contrary, it is smaller, it is long lengthways, and a numeral "2" indicating the face direction is set in the machining direction code CM (Step S4).
Next, a tool path CP is generated according to the machining direction code CM, and it is written in the numerical control information storage section 9. This process is performed in such a way that, when the machining direction code CM is "1", shape elements such as straight lines and arcs forming the machining shape CF stored in sequence are rearranged in such a manner for the Z-coordinate values to be in a descending order, and when the machining direction code CM is "2", shape elements are rearranged in such a manner for the X-coordinate values to be in a descending order, and then they are written in the tool path CP of the numerical control information storage section 9 (Step S5). The line position in the cutting condition table of the machining condition storage section 4 is determined using a material code M in order to read out a cutting speed V (FIG. 2), and a feed speed F and a cutting depth D are written in the feed speed F and the cutting depth D of the numerical control information storage section 9 (FIG. 4) (Step S6). Then, a revolution S is determined by S=1000.times.V/(2.times..pi..times.R) using the cutting speed V and the machining radius R, and this revolution S is written in the number of rotations S of the numerical control information storage section 9 (Step S7).
When the numerical control information is generated, the tool path CP, the machining direction code CM and the cutting conditions are displayed on the display device 2. Thus, the generated numerical control information can be confirmed.
In addition, if the operation buttons or keys corresponding to numerical control information correction are operated, a numerical control information correcting section 8 is invoked. This numerical control information correcting section 8 enables numerical control information to be corrected to further optimized information on the judgement made by the operator. The operations of the numerical control information correcting section 8 will be explained with reference to a flow chart of FIG. 6.
First, guidances concerning such matters as a machining method, cutting conditions and termination are displayed on the display device 2. At the same time, commands from the operator via the operation buttons or keys corresponding to the guidance display are accepted (Step S10), and the contents of the operated command are analyzed and branched according to the command (Step S11). If the command is a machining method, a correction value of the machining direction code CM can be input via the input device 1 by following the guidance display. When the machining direction code CM is corrected, the tool path CP is automatically calculated by the same process as the Step S5 of FIG. 5, and the tool path CP is displayed on the display device 2 (Step S12). When the correction process on the machining method is terminated, the process returns to the Step S10. If the content of the command is a cutting condition, a corresponding guidance is displayed on the display device 2. The input of a new value set via the input device 1 causes the cutting condition to be corrected (Step S13). When the correction process of the cutting conditions is terminated, the process returns to the Step S10. If the content of the command is termination, the numerical control information correction processing is terminated.
When operations corresponding to numerical control information output are input through the input device 1, a numerical control information outputting section 10 is invoked. This numerical control information outputting section 10 allows numerical control information to be converted into such form as an NC program. Thus, it can be retrieved from an output device 11 such as a floppy disk drive device or a paper tape puncher. In a case where this apparatus is incorporated into a numerical control machine tool, the numerical control information outputting section 10 enables numerical control information to be transferred into the NC control machine tool. Thus, direct machining can be performed.
In the above-described numerical control information generating apparatus; an operator does not need to study a machining method before data is input and a novice not familiar with the machining method can handle it with ease. In the case of an experienced operator, it is possible to reduce efforts expended for studying and correcting the numerical control information as required. However, advantages results in the case where cutting conditions are properly set. If the cutting conditions are not proper, they must be corrected. There have been problems in that since there is data pertaining to the kinds of machining, such as cutting machining, groove machining, screw machining, drill machining, and according to each work material, the number of items of cutting conditions is large, and further problems exist in that the relationship between the cutting conditions and the generated numerical control information is difficult to understand if an operator does not to some extent understand the automatic calculation method of the numerical control information generating process, and thus it is difficult for the operator to set cutting conditions properly.